The advantages of high speed machining are many and shops around the world are adapting to this newer technology. One problem everyone must confront is the choice of toolholders, and the HSK toolholders are the most common selection.
What does HSK mean?
This is an abbreviation from the German, meaning, more or less: “hollow shank taper”. Many North American users refer to it as “hollow taper shank tooling”. In German is is “Hohl Shaft Kegel”. This is where the name for HSK toolholders came from.
The reason it was developed was as an attempt to standardize toolholders during a time when there were many competing models and technologies. The goal was to develop a system that was rigid, lightweight, and capable of high radial and axial accuracy. The system also had to be suitable for high speed machining.
The HSK shank types E and F are the ones suitable for high speed applications. It is critical to choose the correct style, not just the right size toolholder. With the wrong HSK toolholders you will never achieve the desired results.
Initially, American and Canadian users were rather disappointed with the results of these tools. It was discovered that the main problem was in the differing machining styles of American and European machinists. The Americans had the practice of greater stock removal rates and this was causing distortion in the holders. The remedy was simply to use the correct grade of tools steel in the construction.
High Speed Machining
HSM presents new problems that must be addressed in order to achieve the results desired. You cannot simply get a high speed spindle and crank up the rpm to 50K and expect good results. The entire process must be integrated.
Carbide cutting tools and carbide inserts are capable of very fast metal removal rates, fine finishes and longevity. When properly used in high speed machining, amazing results will be obtained. The link between cutter and machine is the toolholder, therefore the correct type and size must be used. HSK toolholders are a key component is this process.
Mold making, tool and die and precision machining operations all make extensive use of this technology. EDM electrodes, cores, cavities, contours, coins, and many aerospace components all are done in the HSM.
Shrink Fit Toolholders
One very popular approach is the use of shrink fit tool holders. This ensures an almost perfect fit between the cutter and holder. Once the holder is expanded by means of heat, the cutter is inserted and allowed to cool The shrinking effect locks it in place and eliminates almost all runout and distortion.
Schunk and Kennametal are two of the main toolholder manufacturers in the world. Both carry an extensive line that has been tried and tested in the real world of manufacturing.
HSK toolholders have stood the test of time and are found in tool shops the world over.